This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The primary objective of this proposal is to identify neuroanatomical and neurocognitive predictors of post-operative cognitive dysfunction (POCD) following total knee arthroplasty for individuals 60 and older. While there have been numerous investigations of POCD following cardiac surgery, very little is known about the effects of non-cardiac operations. Recent studies have identified that POCD is most common among adults age 60+ and following major orthopedic surgery, Monk et al., 2001;Moller et al., 198. This is alarming, for older adult communities continue to grow in number throughout the country. Related, as life expectancy increases, it is projected that quality of life surgeries;i.e., total knee arthroplasty, will also increase. If predictors of POCD are identified, the risks associated with these surgeries can be reduced. The present investigation tests the hypothesis that pre-operative neuroanatomical measurements, hippocampus/ entrorhinal cortex, will predict the development of POCD. In addition, we seek to identify whether those individuals who perform poorly on pre-operative neurocognitive measures experiences greater post-surgical cognitive decline. Relationships between the volumetrics, neurocognitive measures, and biochemical markers will also be assessed. The development of POCD will be assessed with cognitive measures at two-weeks, three months, and one-year post surgery. Participants will be obtained in collaboration with the Department of Orthopedics. Their surgery will be performed at Shands Hospital at the University of Florida or the North Florida-South Georgia Veteran?s Administration. The MRI procedures will be performed at the McKnight Brain Institute.